A federal appeals court overturned the death sentence for Dzhokhar Tsarnaev on Friday, ordering a lower court instead to conduct a new penalty-phase trial to determine what sentence the bomber should face for the most severe of his 30 convictions. The appeals judges said the lower court judge “fell short” of sufficiently vetting jurors for biases. The ruling doesn’t affect Tsarnaev’s conviction. Five years ago, Tsarnaev was found guilty of planning and carrying out the 2013 bombing attack on the Boston Marathon that killed three, wounded hundreds, and struck terror into the city. He and his brother Tamerlan, who died in a shootout with police, also hijacked a car in their escape attempt, killing a police officer at MIT in the process.